Many of the automobiles in recent years have a navigation system installed as a driving assistance apparatus. The navigation system displays a road map on a display based on a map data retrieved from a DVD-ROM or the like, having a vehicle position, a path to a destination or the like indicated on the displayed road map. The display of the navigation system uses a liquid crystal display disposed tiltably on a fixing frame. In other words, the display can be tilted in order for a driver of the vehicle to have the best viewing angle in various situations such as adjusting a tilt angle to the height of a driver, avoiding reflection of the sunlight from a window and the like.
The tiltable structure of the display is usually achieved by supporting the top end of the display rotatably on an axis with a torque application mechanism to the display body.
In this type of tiltable structure, a gap can be caused between a lower end of the display and a lower member of the fixing frame when the display is tilted. In a conventional automotive display, the fixing frame of the display has a concave portion at the bottom of the inside area to accommodate the lower end of the display, in order to prevent the gap from being seen from outside.
The navigation system is disposed on a dashboard, typically in the middle of the driver's seat and the passenger's seat. Therefore, the display of the navigation system suffers from a liquid spilt from a cup held by a passenger or a driver when the vehicle stops suddenly.
The spilt liquid collects in the concave portion at a lower inside area of the fixing frame of the display. The collected liquid penetrates into the display. Many electric circuits for the liquid crystal display and the like are disposed in the display, and thus the penetrated liquid causes a short circuit or other damages to the circuit.
Penetration of the spilt liquid into the display can be prevented by devising a drain structure in the concave portion at the bottom of the fixing frame. A patent document JP-A-2002-130092 discloses a groove for draining water in an engine starter including a motor, a speed reduction device, an electromagnetic device, a clutch, and a switch. However, it is difficult to apply the drain structure disclosed in this patent document described above to a display of a navigation system, because of the difference of the mechanism between the starter and the display.